Lateglacial–early Holocene vegetation history of the Tiber delta (Rome, Italy) under the influence of climate change and sea level rise

Abstract

A new pollen and plant macrofossil record from Pesce Luna (Fiumicino, Rome) provides the reconstruction of the vegetation history in the Tiber Delta region between 13,000 and 8400cal. BP. Marked fluctuations of hydro- and hygrophytes depict a variety of marsh–lagoon conditions reflecting marked changes in water-table level and salinity, determined by the transition from a continental environment with a strong fluvial influence, to a freshwater/brackish environment typical of an inner estuary, followed by a saline outer estuary environment. Both deciduous (mostly Quercus, Corylus, Tilia, Ulmus and Fagus) and evergreen elements (evergreen Quercus and Ericaceae) were already present during the Younger Dryas, being possibly enhanced by water availability and the vicinity to the sea that may have favoured long-term persistence of tree populations. Evergreen populations progressively increased during the early Holocene. Despite the strong effect of local environmental processes, a comparison of the Pesce Luna pollen record with other southern European sequences and the GISP2 δ18O record indicates that the vegetation development was also influenced by centennial-scale climate processes acting at global scale. In particular, a mid-Younger Dryas climate reversal can be recognized at Pesce Luna, similar to other Mediterranean sites both in marine and continental environments. This study improves our knowledge on the vulnerability and resilience of coastal-estuarine wetlands to the global warming and sea level rise of the last deglaciation, adding insights into the response of coastal environments to the predicted global climate changes.